Ebullition initiator



July 26, 1932.-

L. LARSEN EBULLII'ION INITIATOR Filed Dec. 16. 1927 m m m [an rams W Zarsen Patented July 26, 1932 glATES PATENT OFFICE RATION SF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN EBULLITIQN INITIATOR Application filed December 16, 1927; Serial No. 240,395.

My invention relates to the art of mechanical refrigeration, and it has particular relation to means for preventing superheating of the refrigerant employed therein.

3 In the artof mechanical refrigeration, it is customary to employ a readily volatilized liquid as a refrigerant, which is moved in a closed cycle within the refrigerating system. In order to properly lubricate the moving parts of the system, a certain amount of counters in passing through the layer of oil disposed on top of the liquid refrigerant, which in turn causes superheating of the refrigerant.

By my invention I have eliminated the aforementioned diiiiculty by providing means whereby superheating of the refrigerant is avoided by providing a path for the ebullition of the refrigerant in which the layer of oil is eliminated, thus permitting the initiation of ebullition as soon as the pressure and temperature reach a point at which ebullition of the specific refrigerant utilized is possible.

One object of my invention is to provide a novel type of ebullition initiator.

Another object of my invention consists in providing an ebullition initiator adapted to be employed in a refrigerating system in which oil in liquid form lies upon the body of liquid refrigerant whereby the retardation of ebullition owing to the presence of oil is obviated.

F or a better understanding of my in ention, reference may now be had to the accompanying drawing of which Fig. 1 is a vertical crosssectional view of an evaporator adapted to be employ d a frigerating system provided with an ebullition initiator constructed in accordance with my invention.

Fig. 2 is a detail cross-sectional view of the ebullition initiator illustrated in Fig. 1.

Referring to the drawing I have illustrated an evaporator which is circular in crosssection and is provided with a plurality of substantially U-shaped tubes 11, both ends of which are in open communication with the lower portion of the tank or evaporator 10. Disposed within the evaporator is a body of liquid refrigerant 12, which may, for eX- ample, be sulphur dioxide. Disposed on top of the layer of sulphur dioxide is a layer of oil 18, preferably an asphaltiobase oil, which is lighter in specific gravity than the sulphur dioxide and which is materially less volatile. Disposed within the evaporator 10 is an arcuate open end tubular member 14, the lower end of which extends well into the body of liquid refrigerant and the upper end 16 of which extends into the upper portion of the evaporator 10 above the level of the body of the oil 13. The member 14 is held in position within the evaporator 10 by means of a resilient adapting member 17 which is secured at one end to the member 14, the opposite end of which is bent into a substantially U-shape and projects into one of the tubes 11, clampingly engaging the walls thereof. As many of the arcuate tubes 14 may be employed in each evaporator as is desired, but experience has shown a single tube is all that is necessary. The evaporator 10 is also provided with an inlet opening 18, usually guarded by a float-operated valve, (not shown), through which a mixture of oil and refrigerant in liquid form is admitted thereto, and an outlet 19 through which the refrigerant in gaseous form together with a certain amount of oil in liquid form is drawn by the compressor (not shown).

Having described the construction of the apparatus embodying my invention, its operation is as follows:

When the compressor of the refrigerating system is started, it draws from the evaporator 10 through the opening 19 all of the gas disposed in the evaporator above the level of the oil, thus producing a partial vacuum therein. The reduction of the pressure within the tank has a tendency to cause the liquid I'IIGAN, ASSIGNOR TO KELVINATOR COR-PO- ,tained therein is immediately gasilied.

refrigerant to become gasilied but this action is retarded by the body of oil 13. However, as little or no oil is contained within the arouate tubular member 1 1, the refrigerant con- As the ebullition oi the liquid within the relatively small tubing 11 is rather violent, the refrigerant is spewed from the end 16 of the tube 1 1 in the form of combined gas and liquid, the liquid being forced upwardly by the gas passing upwardly in the tube. The gas coming from the end 16 of the member 1 1 passes out of the opening 19, and the liquid carried thereby falls on top of the oil 13 and is immediately evaporated. Operation of the member 11, as described, will continue until such time as the gasilied portion of the main body 12 succeeds in breaking through the layer of oil 13, thus raising the pressure within the evaporator 10 and starting ebullition in the proper manner.

From this description it *ill be aoparent that superheating of the refrigerant is prevented by [he use of my invention by reason of the fact that the instant that the pressure and temperature conditions are such thatebullition is possible, it begins vithin the tube l t. The tube 1 1- not only canes ebullition of the refrigerant contained therein but also causes a certain amount of movement of the main refrigerant body 12 which movement is highly conducive to initiating ebullition thereof.

The oil 13 is of such nature that arelatively small amount thereof is soluble in the refrigerant, so that the layer of oil 1?) is a result of the oil in solution being left in the evaporator when the sulphur dioxide vaporizes. It is possible that, after ebullit-ion of the main refrigerant body 12 is well under way, the concurrent ebullition within the member 14 may decrease in violence to such degree that it no longer spews liquid from the top thereof, although refrigerant in gaseous form is emitted therefrom. This condition would leave a thin layer of oil on top of the refrigerant within the tube 14. However, the spewing action which occurs each time the compressor is started, following a period of rest, spews from the tube any oil which may have accumulated therein. The main body of oil 13 is the result of the accumulation of oil from a number of cycles of operation. For this reason it is apparent that the initial resistance to the passage of gasiiied refrigerant through the oil is materially less through the tube 1+1 than from the main body of lubri' cant, as the layer of oil within the tube, if one exists there, is materially thinner than the layer on top of the main body of refrigen ant.

Although I have shown but a single form of my invention and described in detail but a single application thereof, it will be apparent to those skilled in the art that it is not so limited but that various modifications and changes may be effected therein without departing from the spirit of my invention or from the scope of the appended claims.

hat I claim is:

1. In a refrigerating system, an evaporator header adapted to be partly filled with liquid, a plurality of pipe loops communicating with the header, and a hollow tubular member provided with resilient securing means on its external surface, said securing means being adapted to be inserted into a pipe loop for securing the tubular member in position with one extremity above the liquid and the other below the liquid.

2. In a refrigerating system, an evaporator header adapted to be partly tilled with liquid, means providing a plurality of refrigerant passages communicating with the header, and a hollow member provided with securing means on its external surface, said securing means being adapted to cooperate with at least one of said refrigerant passages for securing the hollow member in position with one extremity above the liquid and the other below the liquid.

In testimony whereof I hereunto aflix my signature.

LAWRENCE IV. LARSEN. 

